Fire alarm



Sept. 20, w49..

J. A. JOHNSTON 2,482,113

FIRE ALARM Filed March 16, 1946 um J5 l mmf-"1' f.

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,4free/vir Patented Sept. 20, 1949 UNITED STATES PATENT OFFICE 12 Claims. 1

This invention relates to thermostatically operated alarms and deals more particularly with a fire alarm combined with the alarm mechanism of a clock.

An object of the present invention is to provide an alarm clock embodying a re alarm which will operate whether the clock is operating or not.

Another object of the invention is to provide an alarm clock having a spring operated alarm which will function either at a pre-set time or upon an undue increase in the temperature in the vicinity of the clock.

Another object of the invention is to provide means responsive to increased temperature for setting oil the alarm mechanism of an alarm clock, said means being of simple, inexpensive construction, and adapted for ready incorporation in the clock mechanism without material change in said mechanism.

My invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description. However, the drawings merely show and the following description merely describes one embodiment of the present invention, which is given by way of illustration or example only.

In the drawings, like reference characters designate similar parts in the several views.

Fig. 1 is a top plan view of a typical alarm clock embodying the invention, the clock oase being broken away for clearer illustration.

Fig. 2 is a similar view of the clock mechanism after operation of the alarm mechanism is caused by increased temperature in the vicinity of the clock.

Fig. 3 is a broken rear view of the clock and alarm mechanism.

The alarm clock which is illustrated in the drawing is of generally typical design and it will be apparent that this invention may be embodied in clocks of different form and arrangement. As shown, the invention may be said to comprise, generally, a clock-works I incorporating a timeoperated alarm I l having a signal bell or the like I2, and thermostatically operable means I3 for causing operation of the alarm upon increased or unduly great temperature in the vicinity of the clock. Said means I3 further includes means I4 for automatically shutting off or stopping the functioning of the alarm regardless of whether it was set off thermostatically or by the clockworks.

The clock-Works I0, conventionally, includes a gear train I5, a clock spring for driving the gear train, a gear I'I which is driven from the gear train in timed relation to the hands of the clock, an alarm trip I8 which trips according to a set position as controlled by a manual knob I9, a tension member 2|] movable upon operation of the trip I8 from locking to releasing position with respect to a olapper 2| operably associated with the bell I2. The alarm trip I8 is manually set by means of the knob I9 so that at a predetermined time, the member 20 will release the clapper 2| by moving out of interfering engagement therewith.

The alarm mechanism II, conventionally, includes a spring 22, a handle 23 for winding the spring, a shaft 2li carrying the handle 23 and rotated thereby in one direction when the spring is being wound, `said shaft rotating in the other direction as the spring unwinds, a second shaft 25, gears 26 connecting the shafts 2t and 25, an

escapement wheel 21 on the latter shaft, and an escapement 28 associated with the Wheel 27. The bell clapper 2| is carried by the escapement 28 and moves therewith. Upon release of the clapper, as mentioned, the spring 22 becomes effective to drive the gears 26, rotate the escapement wheel 21 and cause oscillation of the escapement on its trunnions 29. The escapement, of course, controls the release of energy of the spring 22 and its oscillating movement imparts similar movement to the clapper 2| so that the latter intermittently strikes the bell I2. Conventionally, the clock case 30 carries an alarm stop 3| which may be set to engage the clapper 2| and hold the same against movement when the trip I8 functions and an alarm is not desired.

According to the present invention, the abovedescribed conventional alarm clock is converted to function also as a fire alarm by embodying therein the thermostatically operable means I3 and the automatic alarm shut-off means Iii. The clock case 3S is also modified by providing a grille 32 therein to enable circulation around the means i3 of air in the vicinity of the clock.

The means I3 comprises a thermostatic element 33 formed in this instance as a spiral heat sensitive member having its inner end anchored to a post 34 and its outer end 35 extending into an opening in the escapement. Said opening is preferably formed on a line between the trunnions 29 so that the oscillating movement of the escapement is not interfered with by being coupled to the thermostatic element 33. The post 34 is supported on a bracket 36 Which is carried by the frame of the clock-Works I0. The arrangement is such that the end 3'5 of the thermostatic element 33 will move transversely of the clock-works as said element expands and contracts under relatively high and low heat conditions. Thus, as shown in Fig. 1, under low r normal temperature conditions, the escapement 28 will be held in its normal position so that the clapper 2|, which it carries, is in interfering relation to the tension member 2). As shown in Fig. 2, under high or abnormal temperatureI conditions, the escapement will beI movedv laterally on its trunnicns to release the clapper from the member 2Q so that the spring 22 may becomeeffective to oscillate or vibrate the escapement and,y consequently, the clapper 2|. Accordingly, the escapement 28 is modified to decrease the normal distance between its end shoulders 31 to permit the mentioned endwise movement of the escapement as impelled by the thermostatic element 33.

It will be evident that the alarm can be set oi either by timed tripping of the trip I8 to release the tension member 26" from engagement with the clapper 2li, orv by the thermostatic endwise movement of the clapper from holding engagement by the member 20. Although the time controlled operation of the alarm is dependent upon the clock-works being in operation, the thermostatically controlled operation is independent of the clock-Works, it only being` necessary that the spring. 22 is at least partially wound up.

The automatic alarm shut-off |14 comprises an arm 38 mounted on the shaft 24 and extending toward and' beneath an offset 39 of the' clapper 2|. The free end of the arm 38 is shown` as reentrantly bent to form a spring end 13B and rotation of said arm is obviated by engagement thereof with the shaft 25. The hub 4| of the arm is internally threaded for engagement with screw threads 42 which are provided on the shaft 2li. The latter is also formed with a reduced unthreaded part i3 extending from the threaded portion 42 of the shaft. By means of the described arrangement, as the spring 22 unwinds under the control of the escapement and the alarm is operating, the threads G2 act to move the arm 38 from its position as shown in Fig. 1 where it is out of engagement with the offset 39, to a position beneath said offset as shown in Fig. 2. The interfering relation between the offset 3S and the arm 33 will prevent vibration of the clapper 2| and stop the ringing of the bell l2.

Upon rewinding of the spring 22 the arm 38 is restoredv to its initial position .on the part 43 of the spring shaft 24. It will be noted that action of the thermostatic element 33, will first move the escapement and, therefore, the clapper offset 39. away from the arm 38 and, as the spring 22. unwinds during operation of the alarm, said arm will then move to eifect the mentioned engagement with said .offset When winding alarm spring 22, arm- 33 moves laterally off threads 32 onto the unthreaded. part 3310i shaft 24. Said portion-may have a diameter substantially that of the base diameter of threads 43a Consequently, rotation of the shaft 24 can becontinued to fully wind spring v2 without further lateral shifting of arm 38, the' internally 4 threaded hub 4| thereof simply rotationally engaging said reduced portion 43.

It is essential that the heat controlled mechanism of the alarm function whether the time controlled mechanism is shut off by the manual stop 3| or not. To permit the mentioned endwise movement of the escapement with said stop engaged with the .offset 39, the end 44 thereof is arranged at a declining angle as shown best in Fig; 3'. Only slight endwise movement of the escapement is necessary to' effect release of the clapper from detention by the stop 3|.

While I have illustrated and described what I now regard as the preferred embodiment of my invention, the construction is, of course, subject to modifications without departing from the spirit and scope of my invention. I, therefore, do not wish to restrict myself to the particular form of construction illustrated and described, but desire to avail myself of all modifications that may fall within the scope of the appended claims.

Having thus described my invention, what claim and desire to secure by Letters Patent is:

l. An alarm device comprising the time-controlled spring-operated alarm mechanism of an alarm clock and including an escapement and a bell clapper thereon and further including a member having releasable holding engagement with the clapper, and thermostatic means for moving said clapper endwise out of engagement with said member to effect release thereof for alarm-sounding movement by saidv mechanism..

2. An alarm device comprising the time-controlled spring-operated alarm mechanism of an alarm clock and including an; escapement and abell clapper thereon and further including a member having releasable holding engagement with the clapper, a thermostatic element coupled with the escapement and adaptedto move the same out of engagement with said member upon abnormally high temperature in the vicinity of the device to free the clapper for alarm-sounding movement by said mechanism.

3. An alarm device comprising the time-controlled spring-operated alarm mechanism of an alarm clock and including an escapement and a bell clapper controlled by the spring of said mechanism and further including a member having releasable` holding engagement with the clapper, thermostatic means for moving said clapper endwise out of engagement with said member to effect release thereof and thereby free the same for alarm-sounding movement, and means movable by the time-controlled mechanism for automatically re-engaging they clapper subsequent to its release by the mentioned member to arrest said movement of the clapper.

4. In an alarm device, a driving spring, timecontrolled means for releasing the force of said spring, an escapement controlling the rate of release, a bell clapper vibrated by the escapement, a member controlled by the time-controlled means adapted for releasable holding engagement with the clapper, means mounting said clapper for movement away from said member, and thermostatic means for effecting said' latter movement when the temperature in the vicinity of the device becomes abnormallyv high.

5. In an alarm device, a driving spring, timecontrolled means for releasing the force of said spring, an escapement controlling the rate of release, a bell clapper vibrated by the escapement, a member controlled by the time-controlled means adapted for releasable holding engagement with the clapper, means mounting said clapper for movement away from said member, and thermostatic means for effecting said latter movement when the temperature in the vicinity of the device becomes abnormally high, said latter means comprising a spirally wound thermostatic element having its movable end engaged with the escapement.

6. In an alarm device, a driving spring, timecontrolled means for releasing the force of said spring, an escapement controlling the rate of release, a bell clapper vibrated by the escapement, a member controlled by the time-controlled means adapted for releasable holding engagement with the clapper, means mounting said clapper for movement away from said member, thermostatic means for effecting said latter movement when the temperature in the vicinity of the device becomes abnormally high to free the clapper for vibration, and means movable by the time-controlled means for automatically arresting the movement of the clapper subsequent to the mentioned movement of the clapper away from the mentioned member.

7. In an alarm device, a driving spring, timecontrolled means for releasing the force of said spring, an escapement controlling the rate of release, a bell clapper vibrated by the escapement, a member controlled by the time-controlled means adapted for releasable holding engagement with trie clapper, means mounting said clapper for movement away from said member, thermostatic means for effecting said latter movement when the temperature in the vicinity of the device becomes abnormally high to free the clapper for vibration, said latter means comprising a spirally wound thermostatic element having its movable end engaged with the escapement, and means movable by the time-controlled means for automatically arresting the movement of the clapper subsequent to the mentioned movement of the clapper away from the mentioned member.

8. In an alarm device, an escapement, means for mounting the escapement for both oscillating and endwise movement, time-controlled means for releasably holding said escapement immovable and including a member engaged with the escapement, a bell clapper carried by the escapement and movable therewith, and a thermostatic element controlling the endwise movement of tne for mounting the escapement for both oscillating l and endwise movement, time-controlled means for releasably holding said escapement immov- Aio able and including a member engaged with the escapement, a bell clapper carried by the escapement and oscillative therewith to sound an alarm, a thermostatic element controlling the endwise movement of the escapement and the clapper to effect disengagement of the mentioned member and escapement, and means for automatically arresting the oscillating movement of the clapper subsequent to the endwise movement of the escapement as effected by abnormally high temperature in the vicinity of the alarm device.

11. In an alarm device, an escapement, means for mounting the escapement for both oscillating and endwise movement, time-controlled means for releasably holding said escapement immovable and including a member engaged with the escapement, a bell clapper carried by the escapement and oscillative therewith to sound an alarm, a thermostatic element controlling the endwise movement of the escapement and the clapper to effect disengagement of the mentioned member and escapement, and means for automatically arresting the oscillating movement of the clapper subsequent to the endwise movement of the escapement as effected by abnormally high temperature in the vicinity of the alarm device, said latter means comprising an arm, a threaded shaft adapted to move the arm toward the clapper, and an alarm spring for rotating said shaft.

12. In an alarm device, a bell clapper mounted for oscillating movement and for endwise movement between two opposed positions, a thermostatic element connected to the clapper to normally hold the same in one endwise position; a resilient member engaged with the clapper in the latter position and holding the same against 0scillating movement; time-controlled means for eiecting movement of the resilient member to release the clapper; means, including an escapement associated with the clapper, a spring, and a threaded winding shaft for the spring for driving said escapement and thereby oscillating the clapper; and a member threadedly mounted on said threaded shaft and movable thereby, after the mentioned release of the clapper from the resilient member, to eiect subsequent oscillationstopping engagement of the clapper by said member; said thermostatic element, when the temperature in the vicinity of the device is abnormally high, flexing to move the clapper to the other endwise position and thereby effecting disengagement of said clapper from holding engagement with the mentioned resilient member whereby said clapper is released for oscillation and whereby said threaded member is also movable for subse- Name Date Hartley Feb. 22, 1921 Number 

